I am pretty sure that Blizz don't have the time/manpower/recourse to fight bots forever.. Now, this might sound strange to you.. After all Blizzard is owned by a multinational conglomerate and has millions of dollars of disposable income that they can use to fight bots, right? WRONG! Think about it, the way Blizz has changed over the years; the way they managed Diablo 3 to get it to it's current state. It's all been driven by capitalism in it's purest form. They want to make large profits, that's all they are concerned about.
While major cheating and hacking (like duping and copying items and possibly other forms of which we know squat about; maybe even RMAH interference which is directly linked to bank/credit card fraud) are occupying their time, bots should not be such a big deal to them.
Botters are actually buying their game over and over again. Botters are PLAYING their game (even tho automatically) and they benefit from that- selling botted items on the RMAH generates profit for them. Botters are buying stuff for gold of the AH to equip new bots, which more or less keeps the gold economy alive.
Of course they will issue ban waves every now and than, just like politicians do, they will go out and say- look, we just did this and that, so that the common players won't loose their trust. But to them bots are actually more profitable than the common non-botting individuals. This game, as many other games in the past, will evolve to a certain state where bots will be common and a huge percentage of the players will use them. It's logically the most profitable way to manage a game nowadays. There are also many examples of games where this happened, even tho they did not offer RMAH. Think about Lineage 2, Diablo 2. D3 will, in my opinion, be another example. So keep your heads up and welcome a better botting day. im off.